Magnetic dampening unit for an exercise gym apparatus

ABSTRACT

A magnetic dampening unit for an exercise gym apparatus includes a plate and an axle secured on the plate. A flywheel is rotatably mounted on the axle and has a hub. A stub is formed at a central portion of the hub and opposed to the plate. A non-magnetic metal member is provided in the flywheel and faces the plate. A disk is rotatably mounted on the axle and between the flywheel and the plate. A resilient member is mounted on the axle and between the disk and the plate. Multiple permanent magnets are provided on the disk with an alternate arrangement of N-polarities and S-polarities and facing the non-magnetic metal member. Two cables are provided on the disk and extend out from the plate. When drilling the flywheel for a dynamic balance, material waste will not be drawn to the magnets and the flywheel can be easily cleaned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an exercise gym apparatus, and moreparticularly to a magnetic dampening unit for an exercise gym apparatus

2. Description of Related Art

With reference to FIG. 3, in a conventional exercise gym apparatus, amagnetic dampening unit has an axle (48) mounted on a plate (50). Aflywheel (40) is rotatably mounted on the axle (48), and a non-magneticmetal member (46) is mounted between flywheel (40) and the plate (50). Aresilient member (49) is mounted on the axle (48) and between thenon-magnetic metal member (46) and the plate (50). The flywheel (40) hasa hub (41) and a stub (42) formed at a center of the hub (41). Bearings(421) are provided in the stub (42) to rotatably mount the flywheel (40)on the axle (48). A belt (60) is provided on the stub (42) and connectedto a crank (not shown) of the exercise gym apparatus.

A recess (43) is defined in the flywheel (40) and faces the non-magneticmetal member (46). An iron member (44) is provided in the recess (43)and multiple permanent magnets (45) are mounted on the iron member (44)with an alternate arrangement of N-polarities and S-polarities to facethe non-magnetic metal member (46). Two cables (47) fixed on thenon-magnetic metal member (46) and extend out from the plate (50). Thecables (47) are connected to an adjusting device (not shown) and can bepulled to a gap between the non-magnetic metal member (46) and thepermanent magnets (45). Then, a distribution of magnetic forces of thepermanent magnets (45) is changed so as to adjust a dampening force ofthe flywheel (40).

The flywheel (40) must be machined carefully in manufacture to achievethe necessary dynamic balance for vibration-free operation when fittedto the apparatus. A common method for achieving dynamic balance isdrilling at proper portions of the flywheel (40). Because the flywheel(40) is made of iron, the small amounts of waste material cut from theflywheel (40) will be drawn by the permanent magnets (45) to stilladhere to the flywheel (40), and it is difficult to clear away the wastematerial. Furthermore, as the permanent magnets (45) are directlyprovided in the flywheel (40), the flywheel (40) itself may becomemagnetized such that the magnetic forces of the permanent magnets (45)are weakened. Therefore, the dampening force of the dampening unit willbecome low.

Therefore, the invention provides a magnetic dampening unit for a gymapparatus to mitigate or obviate the aforementioned problems.

SUMMARY OF THE INVENTION

The main objective of the present invention is to provide a magneticdampening unit for an exercise gym apparatus that can be easilyconfigured for a dynamic balance.

Other objectives, advantages and novel features of the invention willbecome more apparent from the following detailed description when takenin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of a magnetic dampening unit inaccordance with the present invention;

FIG. 2 is a cross sectional view of the magnetic dampening unit inadjustment; and

FIG. 3 is a cross sectional view of a conventional magnetic dampeningunit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to FIGS. 1 and 2, a magnetic dampening unit for anexercise gym apparatus in accordance with the present invention includesan axle (17) mounted on a plate (20) of the exercise gym apparatus (notshown). A flywheel (10) is rotatably mounted on the axle (17). Theflywheel (10) is made of plastic material and provided with an iron ring(1101) embedded therein by means of injection molding. The flywheel (10)has a hub (11), and a stub (12) is formed at a central portion of thehub (11) and opposed to the plate (20). Multiple bearings (121) arereceived in the stub (12) to rotatably install the flywheel (10) on theaxle (17). A recess (13) is defined in the flywheel (10) and faces theplate (20).

A disk (15) made of a non-magnetic metal is movably mounted on the axle(17) and received in the recess (13). A resilient member (18) isprovided on the axle (17) between the disk (15) and the plate (20).Multiple permanent magnets (16) are mounted on an interior side of thedisk (15) with an alternate arrangement of N-polarities andS-polarities. A non-magnetic metal member (14) is mounted in the recess(13) and faces the permanent magnets (16). Two first cables (19) areformed on an exterior side of the disk (15) and extend out from theplate (20). A belt (30) is provided on the stub (12) and connected to awheel (not shown) for driving the magnetic dampening unit.

A pulley (21) is provided on the plate (20) and the first cables (19)are fastened on the pulley (21). A second cable (22) is fastened on thepulley (21) and connected to an adjusting device (not shown). When thepulley (21) is turned by the second cable (22), the first cables (19)can be pulled to move the disk (15) along the axle (17) so as to adjusta gap between the permanent magnets (16) and the non-magnetic metalmember (14). Then, the distribution of the magnetic force of the disk(15) is changed, and the dampening effect of the flywheel (10) isadjusted.

Because the permanent magnets (16) are provided in the disk (15) andseparated from the flywheel (10), waste material cut from the flywheel(10) during drilling for dynamic balance of the flywheel (10) will notbe drawn to the permanent magnets (16) and the flywheel (10) can beeasily cleaned. Moreover, the permanent magnets (16) are providedadjacent to the non-magnetic metal member (14) and the disk (15), so themagnetic forces of the permanent magnets (16) will not be weakened.

It is to be understood, however, that even though numerouscharacteristics and advantages of the present invention have been setforth in the foregoing description, together with details of thestructure and function of the invention, the disclosure is illustrativeonly, and changes may be made in detail, especially in matters of shape,size, and arrangement of parts within the principles of the invention tothe full extent indicated by the broad general meaning of the terms inwhich the appended claims are expressed.

1. A magnetic dampening unit for an exercise gym apparatus, the magneticdampening unit comprising: a plate (20); an axle (17) secured on theplate (20); a flywheel (10) rotatably mounted on the axle (17), theflywheel (10) having a hub (11), a stub (12) formed at a central portionof the hub (11) and opposed to the plate (20), a non-magnetic metalmember (14) provided in the flywheel (10) and facing the plate (20); adisk (15) movably mounted on the axle (17) and between the flywheel (10)and the plate (20); a resilient member (18) mounted on the axle (17) andbetween the disk (15) and the plate (20); a plurality of permanentmagnets (16) provided on the disk (15) with an alternate arrangement ofN-polarities and S-polarities and facing the non-magnetic metal member(14); two first cables (19) provided on the disk (15) and extending outfrom the plate (20); and a belt (30) provided on the stub (12).
 2. Themagnetic dampening unit as claimed in claim 1, wherein the flywheel (10)has two bearings (121) provided in the stub (12) for rotatablyinstalling the flywheel (10) on the axle (17).
 3. The magnetic dampeningunit as claimed in claim 1, wherein the flywheel (10) has a recess (13)defined at a side facing the plate (20), the non-magnetic metal member(14) is formed in the recess (13) and the disk (15) is located in therecess (13).
 4. The magnetic dampening unit as claimed in claim 3,wherein the balance (10) is made of plastic material by means ofinjection molding and provided with an iron ring (101) embedded in theflywheel (10).
 5. The magnetic dampening unit as claimed in claim 1,further comprising a pulley (21) provided on the plate (20), the firstcables (19) having distal ends fastened on the pulley (21).
 6. Themagnetic dampening unit as claimed in claim 5, further comprising asecond cable (22) fastened on the pulley (21).